This invention relates generally to rotating machines having a wet sump bearing-housing and more particularly to a lubrication system for the bearings supporting-horizontal shafts of such rotating machines.
Machines with non-pressurized lubrication systems are commonly made with splash lubrication provisions, for example oil scoops of the type often supplied on bearing caps on horizontal crankshafts of reciprocating engines. A lubrication system is needed because it is necessary to keep the lubricant level low enough to avoid flooding the bearings and seals surrounding the crankshaft. Such crankshafts have main bearing journals and eccentric rod bearing journals with counterweights to balance the off-center rod bearing journals. The crankshafts are installed by setting them in place on the split main bearing saddles and fastening mating bearing caps over them. Connecting rods are rotatably connected to the eccentric crankshaft throws using rod bearing journal saddles and caps similar to those of the main bearings. When the crankshaft is rotated, the throws alternately dip into an oil sump in an oil pan, which surrounds the crankshaft, and throw oil about the inside of the engine to lubricate the moving parts.
In non-reciprocating machines, there are three ways of lubricating, namely 1) throwers which dip into a lubricant sump to splash lubricate the machine; 2) lubricant slingers which are mounted on the shafts to provide splash lubrication from low-level wet sumps; and 3) flooded lubrication, shown in FIG. 1, where bearings 20 and seals 21 are partially immersed in a lubricant bath and lubrication occurs by bearing ball or roller rotation. This bearing motion intensifies lubricant shear which raises its temperature, reduces its viscosity, and reduces its lubricating efficiency. To avoid these limitations of flooded sump lubrication systems, attempts have been made to reduce lubricant level by using devices which extend radially from the shaft to dip into the lubricant sump. For example, oiling rings which hang eccentrically from the horizontal shaft, as seen in FIG. 3, are used to dip into low level wet sumps to throw lubricant about in the machine. However, they must be driven through slippage by the shaft at a reduced speed. Many factors influence the operating speed of the oiling ring, such as oiling ring weight, lubricant viscosity, buoyancy force, and depth of oiling ring immersion in the lubricant sump. Any significant variation in any of these parameters may tend to limit the lubricating capabilities and stability of the oiling ring. Furthermore, oiling ring lubrication is not suitable for applications involving frequent starts and stops; because the rings tend to become unstable and bounce during starting and stopping. Lubricant discoloration occurs when material is removed from the ring and/or the shaft due to the relative slippage or bouncing of the oiling ring with respect to the shaft.
Another example of lubrication systems for non-reciprocating machines is the use of a solid disc flinger which is driven directly by the shaft and rotates at shaft speed without slippage. This device is illustrated in FIG. 2. Since the solid disk flinger has no eccentricity, it cannot provide lubrication from low-level wet sumps. The outside diameter of the solid disk must be smaller. than the housing bore; therefore, it requires a higher level wet sump which may partially submerge the bearings and flood seals 21 around the horizontal shaft during operation, thereby leading to lubricant leakage through the seals 21. The partially submerged bearings cause more lubricant shear which increases the lubricant sump temperature and reduces the effectiveness of the lubricant.
Housings of horizontal-axis non-reciprocating machines are often made with walls having bearing mounting holes bored through them rather than being axially split to permit radial separation of the housing and to thereby permit sideways installation of the shaft. Thus, shafts in those machines must be installed axially through bearing bores in the housings, and anything on the shafts which extends beyond the radius of the bores must be eliminated. This restriction severely limits splash lubrication capability in non-flooded machines, since shaft-mounted slingers that fit through the bearing bores cannot reach the lubricant in low-level wet sumps.
The foregoing illustrates limitations known to exist in present horizontal shaft machines which have one-piece housings. Thus, it would clearly be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing a lubricant flinger for supplying lubricant fluid to bearings on a horizontal shaft within a wet-sump bearing housing, the flinger comprising a rotationally balanced body having portions extending radially. sufficiently to reach below a lubricant level in the wet-sump; means for fixing said body on said horizontal shaft; and means for permitting insertion of the body, mounted on the horizontal shaft, into the housing through a bearing bore of radius smaller than that of said body.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.